Significant Customers	9 Months Ended
Sep. 30, 2018
Significant Customers [Abstract]
Significant Customers	SIGNIFICANT CUSTOMERS DHL The Company has had long term contracts with DHL Network Operations (USA), Inc. and its affiliates ("DHL") since August 2003. Revenues from aircraft leases and related services performed for DHL were approximately 27% and 27% of the Company's consolidated revenues from continuing operations for the three and nine month periods ending September 30, 2018, respectively, compared to 25% and 25% for the corresponding periods of 2017. Revenues excluding directly reimbursed expenses from continuing operations performed for DHL comprised approximately 32% and 31% of the Company's consolidated revenues from continuing operations for the three and nine month periods ending September 30, 2017. The Company’s balance sheets include accounts receivable with DHL of $12.3 million and $15.7 million as of September 30, 2018 and December 31, 2017, respectively. The Company leases Boeing 767 aircraft to DHL under both long-term and short-term lease agreements. Under a separate crew, maintenance and insurance (“CMI”) agreement, the Company operates Boeing 767 aircraft that DHL leases from the Company. Pricing for services provided through the CMI agreement is based on pre-defined fees, scaled for the number of aircraft operated and the number of flight crews provided to DHL for its U.S. network. The Company provides DHL with scheduled maintenance services for aircraft that DHL leases. The Company also provides Boeing 767 and Boeing 757 air cargo transportation services for DHL through additional ACMI agreements in which the Company provides the aircraft, crews, maintenance and insurance under a single contract. Revenues generated from the ACMI agreements are typically based on hours flown. The Company also provides ground equipment, such as power units, air starts and related maintenance services to DHL under separate agreements. Amazon The Company has been providing freighter aircraft and services for cargo handling and logistical support for Amazon.com Services, Inc. ("ASI"), successor to Amazon Fulfillment Services, Inc., a subsidiary of Amazon.com, Inc. ("Amazon") since September 2015. On March 8, 2016, the Company entered into an Air Transportation Services Agreement (the “ATSA”) with ASI, pursuant to which CAM leases 20 Boeing 767 freighter aircraft to ASI, including 12 Boeing 767-200 freighter aircraft for a term of five years and eight Boeing 767-300 freighter aircraft for a term of seven years. The ATSA also provides for the operation of those aircraft by the Company’s airline subsidiaries, and the management of ground services by the Company's subsidiary LGSTX Services Inc. ("LGSTX"). The ATSA became effective on April 1, 2016 and has a term of five years. CAM owns all 20 of the Boeing 767 aircraft that are leased and operated under the ATSA. Revenues from continuing operations performed for Amazon comprised approximately 31% and 29% of the Company's consolidated revenues from continuing operations for the three and nine month periods ending September 30, 2018, respectively, compared to 45% and 42% for the corresponding periods of 2017. Revenues excluding directly reimbursed expenses from continuing operations performed for Amazon comprised approximately 27% and 27% of the Company's consolidated revenues from continuing operations for the three and nine month period ending September 30, 2017. The Company’s balance sheets include accounts receivable with Amazon of $37.3 million and $44.2 million as of September 30, 2018 and December 31, 2017, respectively. In conjunction with the execution of the ATSA, the Company and Amazon entered into an Investment Agreement and a Stockholders Agreement on March 8, 2016. The Investment Agreement calls for the Company to issue warrants in three tranches which will grant Amazon the right to acquire up to 19.9% of the Company’s outstanding common shares as described below. The first tranche of warrants, issued upon the execution of the Investment Agreement and all of which are now fully vested, granted Amazon the right to purchase approximately 12.81 million ATSG common shares, with the first 7.69 million common shares vesting upon issuance on March 8, 2016, and the remaining 5.12 million common shares vesting as the Company delivered additional aircraft leased under the ATSA. The second tranche of warrants, which were issued and vested on March 8, 2018, grants Amazon the right to purchase approximately 1.59 million ATSG common shares. The third tranche of warrants will be issued and vest on September 8, 2020, and will grant Amazon the right to purchase such additional number of ATSG common shares as is necessary to bring Amazon’s ownership to 19.9% of the Company’s pre-transaction outstanding common shares measured on a GAAP-diluted basis, adjusted for share issuances and repurchases by the Company following the date of the Investment Agreement and after giving effect to the warrants granted. The exercise price of the warrants is $9.73 per share, which represents the closing price of ATSG’s common shares on February 9, 2016. Each of the three tranches of warrants are exercisable in accordance with its terms through March 8, 2021. The Company anticipates making available the common shares required for the underlying warrants through a combination of share repurchases and the issuance of additional shares. The Company’s accounting for the warrants has been determined in accordance with the financial reporting guidance for equity-based payments to non-employees and for financial instruments. The warrants issued to Amazon as of March 8, 2016, were recorded to stockholders equity, having a fair value of $4.89 per share. At that time, the fair value of the 7.69 million vested warrants issued to Amazon was recorded as a lease incentive asset and is being amortized against revenues over the duration of the aircraft leases. On May 12, 2016, the Company’s stockholders approved an amendment to the Certificate of Incorporation of the Company at the annual meeting of stockholders to increase the number of authorized common shares and to approve the warrants in full as required under the rules of the Nasdaq Global Select Market. The stockholders' approval enabled features of the warrants that required the vested warrants of the first tranche and the warrants of the second and third tranches to be classified as financial instruments as of May 12, 2016. Accordingly, the fair value of those warrants was measured and classified in liabilities on that date. Since May 12, 2016, 5.12 million additional warrants in the first tranche vested in conjunction with the execution of eight aircraft leases. As of September 30, 2018, the Company's liabilities reflected 14.83 million warrants having a fair value of $12.55 per share. The re-measurements of the warrants to fair value resulted in non-operating gains before the effect of income taxes of $17.3 million and $25.0 million for the three and nine month periods ended September 30, 2018, respectively, compared to non-operating losses of $35.0 million and $100.6 million for the corresponding periods of 2017. The Company's earnings in future periods will be impacted by the number of warrants granted, the re-measurements of warrant fair value, amortizations of the lease incentive asset and the related income tax effects. For income tax calculations, the value and timing of related tax deductions will differ from the guidance described above for financial reporting. U.S. Military A substantial portion of the Company's revenues is also derived from the U.S. Military. The U.S. Military awards flights to U.S. certificated airlines through annual contracts and through temporary "expansion" routes. Revenues from services performed for the U.S. Military were approximately 9% and 10% of the Company's total revenues from continuing operations for the three and nine month periods ending September 30, 2018, respectively, compared to 7% and 7% for the corresponding periods of 2017. Revenues excluding directly reimbursed expenses from continuing operations performed for the U.S. Military comprised approximately 10% and 10% of the Company's consolidated revenues from continuing operations for the three and nine month periods ending September 30, 2017. The Company's balance sheets included accounts receivable with the U.S. Military of 4.0 million and 6.7 million as of September 30, 2018 and December 31, 2017, respectively.

SIGNIFICANT CUSTOMERS

DHL

The Company has had long term contracts with DHL Network Operations (USA), Inc. and its affiliates ("DHL") since August 2003. Revenues from aircraft leases and related services performed for DHL were approximately 27% and 27% of the Company's consolidated revenues from continuing operations for the three and nine month periods ending September 30, 2018, respectively, compared to 25% and 25% for the corresponding periods of 2017. Revenues excluding directly reimbursed expenses from continuing operations performed for DHL comprised approximately 32% and 31% of the Company's consolidated revenues from continuing operations for the three and nine month periods ending September 30, 2017. The Company’s balance sheets include accounts receivable with DHL of $12.3 million and $15.7 million as of September 30, 2018 and December 31, 2017, respectively.

The Company leases Boeing 767 aircraft to DHL under both long-term and short-term lease agreements. Under a separate crew, maintenance and insurance (“CMI”) agreement, the Company operates Boeing 767 aircraft that DHL leases from the Company. Pricing for services provided through the CMI agreement is based on pre-defined fees, scaled for the number of aircraft operated and the number of flight crews provided to DHL for its U.S. network. The Company provides DHL with scheduled maintenance services for aircraft that DHL leases. The Company also provides Boeing 767 and Boeing 757 air cargo transportation services for DHL through additional ACMI agreements in which the Company provides the aircraft, crews, maintenance and insurance under a single contract. Revenues generated from the ACMI agreements are typically based on hours flown. The Company also provides ground equipment, such as power units, air starts and related maintenance services to DHL under separate agreements.

Amazon

The Company has been providing freighter aircraft and services for cargo handling and logistical support for Amazon.com Services, Inc. ("ASI"), successor to Amazon Fulfillment Services, Inc., a subsidiary of Amazon.com, Inc. ("Amazon") since September 2015. On March 8, 2016, the Company entered into an Air Transportation Services Agreement (the “ATSA”) with ASI, pursuant to which CAM leases 20 Boeing 767 freighter aircraft to ASI, including 12 Boeing 767-200 freighter aircraft for a term of five years and eight Boeing 767-300 freighter aircraft for a term of seven years. The ATSA also provides for the operation of those aircraft by the Company’s airline subsidiaries, and the management of ground services by the Company's subsidiary LGSTX Services Inc. ("LGSTX"). The ATSA became effective on April 1, 2016 and has a term of five years. CAM owns all 20 of the Boeing 767 aircraft that are leased and operated under the ATSA.

Revenues from continuing operations performed for Amazon comprised approximately 31% and 29% of the Company's consolidated revenues from continuing operations for the three and nine month periods ending September 30, 2018, respectively, compared to 45% and 42% for the corresponding periods of 2017. Revenues excluding directly reimbursed expenses from continuing operations performed for Amazon comprised approximately 27% and 27% of the Company's consolidated revenues from continuing operations for the three and nine month period ending September 30, 2017. The Company’s balance sheets include accounts receivable with Amazon of $37.3 million and $44.2 million as of September 30, 2018 and December 31, 2017, respectively.

In conjunction with the execution of the ATSA, the Company and Amazon entered into an Investment Agreement and a Stockholders Agreement on March 8, 2016. The Investment Agreement calls for the Company to issue warrants in three tranches which will grant Amazon the right to acquire up to 19.9% of the Company’s outstanding common shares as described below. The first tranche of warrants, issued upon the execution of the Investment Agreement and all of which are now fully vested, granted Amazon the right to purchase approximately 12.81 million ATSG common shares, with the first 7.69 million common shares vesting upon issuance on March 8, 2016, and the remaining 5.12 million common shares vesting as the Company delivered additional aircraft leased under the ATSA. The second tranche of warrants, which were issued and vested on March 8, 2018, grants Amazon the right to purchase approximately 1.59 million ATSG common shares. The third tranche of warrants will be issued and vest on September 8, 2020, and will grant Amazon the right to purchase such additional number of ATSG common shares as is necessary to bring Amazon’s ownership to 19.9% of the Company’s pre-transaction outstanding common shares measured on a GAAP-diluted basis, adjusted for share issuances and repurchases by the Company following the date of the Investment Agreement and after giving effect to the warrants granted. The exercise price of the warrants is $9.73 per share, which represents the closing price of ATSG’s common shares on February 9, 2016. Each of the three tranches of warrants are exercisable in accordance with its terms through March 8, 2021. The Company anticipates making available the common shares required for the underlying warrants through a combination of share repurchases and the issuance of additional shares.

The Company’s accounting for the warrants has been determined in accordance with the financial reporting guidance for equity-based payments to non-employees and for financial instruments. The warrants issued to Amazon as of March 8, 2016, were recorded to stockholders equity, having a fair value of $4.89 per share. At that time, the fair value of the 7.69 million vested warrants issued to Amazon was recorded as a lease incentive asset and is being amortized against revenues over the duration of the aircraft leases. On May 12, 2016, the Company’s stockholders approved an amendment to the Certificate of Incorporation of the Company at the annual meeting of stockholders to increase the number of authorized common shares and to approve the warrants in full as required under the rules of the Nasdaq Global Select Market. The stockholders' approval enabled features of the warrants that required the vested warrants of the first tranche and the warrants of the second and third tranches to be classified as financial instruments as of May 12, 2016. Accordingly, the fair value of those warrants was measured and classified in liabilities on that date. Since May 12, 2016, 5.12 million additional warrants in the first tranche vested in conjunction with the execution of eight aircraft leases. As of September 30, 2018, the Company's liabilities reflected 14.83 million warrants having a fair value of $12.55 per share. The re-measurements of the warrants to fair value resulted in non-operating gains before the effect of income taxes of $17.3 million and $25.0 million for the three and nine month periods ended September 30, 2018, respectively, compared to non-operating losses of $35.0 million and $100.6 million for the corresponding periods of 2017.

The Company's earnings in future periods will be impacted by the number of warrants granted, the re-measurements of warrant fair value, amortizations of the lease incentive asset and the related income tax effects. For income tax calculations, the value and timing of related tax deductions will differ from the guidance described above for financial reporting.

U.S. Military

A substantial portion of the Company's revenues is also derived from the U.S. Military. The U.S. Military awards flights to U.S. certificated airlines through annual contracts and through temporary "expansion" routes. Revenues from services performed for the U.S. Military were approximately 9% and 10% of the Company's total revenues from continuing operations for the three and nine month periods ending September 30, 2018, respectively, compared to 7% and 7% for the corresponding periods of 2017. Revenues excluding directly reimbursed expenses from continuing operations performed for the U.S. Military comprised approximately 10% and 10% of the Company's consolidated revenues from continuing operations for the three and nine month periods ending September 30, 2017. The Company's balance sheets included accounts receivable with the U.S. Military of 4.0 million and 6.7 million as of September 30, 2018 and December 31, 2017, respectively.